Sandy Predicted to Morph Into a Post-Tropical Cyclone

Monday morning has dawned, and it's raining again here in not so sunny South West England. Over on the other side of the Atlantic the news about Hurricane Sandy hasn't improved overnight.  Here's how the latest National Hurricane Center prediction looks at the moment:

NHC forecast track for Hurricane Sandy at 08:00 EDT on Monday October 29, 2012

According to the latest public advisory bulletin from the NHC:

SANDY NOW MOVING NORTH-NORTHWESTWARD AND ACCELERATING. MAXIMUM SUSTAINED WINDS 85 MPH. A TURN TOWARD THE NORTHWEST IS EXPECTED LATER THIS MORNING, FOLLOWED BY A TURN TOWARD THE WEST-NORTHWEST TONIGHT. ON THE FORECAST TRACK THE CENTER OF SANDY WILL MOVE OVER THE COAST OF THE MID-ATLANTIC STATES THIS EVENING OR TONIGHT.

SANDY IS EXPECTED TO TRANSITION INTO A FRONTAL OR WINTERTIME LOW PRESSURE SYSTEM PRIOR TO LANDFALL. HOWEVER THIS TRANSITION WILL NOT BE ACCOMPANIED BY A WEAKENING OF THE SYSTEM AND IN FACT A LITTLE STRENGTHENING IS POSSIBLE DURING THIS PROCESS.

Once that transition occurs Sandy will no longer be officially classified as a "hurricane", and the NHC will stop issuing regular bulletins on her progress. That task will be taken over by the US National Weather Service's Hydrometeorological Prediction Center (or HPC for short).

Whilst we all wait for that to happen, here's a map of the New York City flood evacuation zones:

Note that the red Zone A is already subject to the:

Mandatory evacuation ordered by Mayor Bloomberg.

and that the blue dots show the location of evacuation centers. If you don't live in NYC itself try clicking the link near the bottom of the key, and then you will be able to explore evacuation zones a bit further afield on the United States eastern seaboard. Apart from potential flooding, a problem that will affect many more people is an electric power outage. Water will obviously cause problems with electricity supplies, but so will Sandy's winds. According to the NHC once more:

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 175 MILES FROM THE CENTER, AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 485 MILES

Those winds will fell trees, which will take overhead power lines with them. By our calculations at least 3.5 million "electricity customers" were without power at one point during the passage of Hurricane Irene last year. When I started writing this post that number for "The Bride of Frankenstorm" was about 35,000. It will be a lot worse than that by now.